Scintillation characteristics of nonstoichiometric phases formed in MF2-GdF3-CeF3 systems - Part III. Dense Gd1-x-yMxCeyF3-x tysonite-related crystals (M = Ca, Sr)

We evaluated the scintillation characteristics and the radiation hardness o f Gd1-xCaxF3-x and Gd1-xSrxF3-x tysonite-type solid solutions (close to 6.6 g/cm(3) in density) doped with Ce which were grown from the congruent melt . As the Ce concentration increased, the Ce3+ emission at 345 nm increased to a level comparable with the Gd3+ emission at 310 nm. Both emissions, how ever, were slow with the decay constant in the order of ms. The radiation h ardness, which was roughly 10(4) rad, tends to degrade as the wavelength de creases and/or the Ce concentration increases. Both spontaneous recovery an d UV annealing of the radiation damages were significant. The intensity of the gamma-ray excited luminescence, integrated over time, was as large as 5 0% of that in BaF2 (12% of that in CdWO4). When the Ce concentration is nil or only small, the yellow-green luminescence for UV excitation was as inte nse as in CdWO4. Although the present crystals are not good for the applica tions in high-energy physics experiments, they may find applications in dis play devices, thermal neutron monitors, etc. (C) 1999 Elsevier Science B.V. All rights reserved.